If we look at Real Madrid's performance in their last 4 matches in various competitions then we should now be confident that Real Madrid will also succeed in winning this 8th match against Brest. Brest may be stronger than RB Salzburg and maybe this match will not be an easy match like when Real Madrid beat RB Salzburg. Because Brest is currently superior in the UCL standings to Real Madrid. But with Real Madrid's maximum performance, Real Madrid should still be in a superior position even though they are only guests in today's match. The only thing that can make Real Madrid lose is if Real Madrid returns to their worst performance again. But I don't think that will happen.
I will have to agree with you that Real Madrid is the favorite in this match. With the rejuvenation of Kylian Mbappe, Real seems to be moving like a train that cannot be stopped. The defense might not be as strong as it used to be but the attack will always score. I am beginning to see a perfect synergy between Vinicius, Rodrigo, and the French striker. But the Galacticos should not underrate Brest. In five games, the French side has won four. This underdog has also won some big clubs in the UCL. Brest thrashed Barcelona and also won PSV. This match is a must-win for both sides for them to move to the next round.